1. Field of the Invention
This invention relates to a receptacle type ground-fault circuit interrupter.
2. Description of the Related Art
Conventional receptacle type reground-fault circuit interrupter (GFCI) device typically includes a faceplate, a middle frame, a bottom case, a grounding frame assembly, input terminals, output terminals, copper outlets, a ground-fault current detector, a reset and trip device, a reset button assembly and a test button assembly. The input terminals and copper outlets are integrally made and electrically connected. The reset and trip device includes an electromagnetic coil, an iron core, dynamic contact sheets, static contact sheets, a dynamic contact bridge, an L-shape retaining plate, reverse dynamic contact sheets and reverse static contact sheets. The reset button assembly includes a reset button, a button shaft and a reset spring, where one end of the button shaft has a thin shaft with a convex stage. The long edge of the L-type retaining plate has a through-hole and is inserted into an insertion hole in the horizontal direction of the dynamic contact bridge. The reverse dynamic contact sheets and the pair of reverse static contact sheets are on the lower side of the dynamic contact bridge.
Conventional GFCI devices of this structure have the following shortcomings. a) The reset button can reset the GFCI when the input and output terminals of GFCI are correctly wired, and cannot reset it when the terminals are reversely wired, thereby indicating that there is a mistake with the wiring. However, although it provides certain degree of reverse-wiring protection by preventing the reset, it only provides an indicating, and the output terminals are still powered and thus the user is still in danger of electrical shock. b) If a wire of the input terminal breaks or falls off from the input conductors when the GFCI is in normal use, the GFCI will not trip automatically, and thus remains in the reset state. There would be no great harm if it is a phase line that is broken or loose, but if it is the neutral line that is broken or loose, the electric potential at the output terminal or the copper outlets is equal to that of the input terminal, which will form an electric path through a human body. If a person gets electric shock on the copper outlets or the output terminal in this instance, the GFCI will not provide a protection function. c) There is no indication when the GFCI is damaged, causing users to continue to use it without being aware of the defect, therefore exposing themselves to the danger of electrical shock.